Hi i would have thought the same but read this :-
When rigged up using analogue ports, the BD80 does a great job with both Hellboy II 's DTS-HD MA and The Dark Knight’s Dolby True HD soundtracks. Channel separation is clean, rear effects are smoothly steered and dialogue is distinct, and I was particularly impressed by the breakneck car chase through Gotham City, which the BD80 orchestrates with exhilarating vigour. It sucks you right in and spits you out the other end, battered but buzzing.

any ideas also

But what does that £100 premium over the DMP-BD60 get you? For starters, the DMP-BD80 adds 7.1-channel analogue audio outputs, which will appeal to owners of older amps who want to savour the hi-res delights of Dolby TrueHD and DTS HD Master Audio. The unit decodes these formats into uncompressed PCM without compromising their sound quality, and outputs them as analogue signals from these ports. The BD80 also features superior audio circuitry to the BD60.